put 2 copies of the invoice in the envelope. on one of them stamp "copy" on it. send a letter the first time so your clients know what you are doing and what is expected. keep the lines of communication open. that is very important.

It uses NEBS invoice paper that has a perfed bottom portion. Problem is the Y2K version of this program did away with the ability to have a message in the perfed area, so its not as useful now. It IS good for folding though! Just fold the 1.5" perf and then fold again in half. Stuff in the 2 window envelope and your done.

I simply put the message "Please enclose invoice number on check" on every invoice. They keep all of it. The people that are returning your whole invoice are probably copying it on a copier!?

Another thing to get is pre-addressed retrun envelopes. It speeds up payment nicely! Everytime postage goes up, I include NEW postage on this as a little perk for them! Ordinarilary they go out without postage though!

As long as your staying at your current address, buy them in BULK, they're pretty cheap!

i got mine at office max. it is a paper cutter with inner changable blades, the blade for perferation runs like $9.00. i can do two pages at a time, but it is quick, the cutter runs around $50.00. i used to have it done at a printing shop, but the paper would bind up in my printer, but no more. check out office max.

You can buy a tool to do this yourself but I just have my invoices printed up and get them pre-perforated. It all boils down to do you have time to do this yourself you do you just want to pay and have it done for you?

I do my billing using MS Office products and I have always just sent two copies of the invoice... one white and one canary (light yellow). I keep a stack of alternating colors ready for the printer at the end of the month.

I also have "Please return white copy with payment. Retain yellow copy for your records." printed just above the bottom of the page. So far everyone has figured it out.